From 8fb2ff458ba579dba08bfdf57d043ad158b5db07 Mon Sep 17 00:00:00 2001
From: Jeroen Bakker <jbakker>
Date: Mon, 17 Jan 2022 14:32:03 +0100
Subject: GPUShaderCreateInfo for interface abstraction

This is a first part of the Shader Create Info system could be.

A shader create info provides a way to define shader structure, resources
and interfaces. This makes for a quick way to provide backend agnostic
binding informations while also making shader variations easy to declare.

- Clear source input (only one file). Cleans up the GPU api since we can create a
  shader from one descriptor
- Resources and interfaces are generated by the backend (much simpler than parsing).
- Bindings are explicit from position in the array.
- GPUShaderInterface becomes a trivial translation of enums and string copy.
- No external dependency to third party lib.
- Cleaner code, less fragmentation of resources in several libs.
- Easy to modify / extend at runtime.
- no parser involve, very easy to code.
- Does not hold any data, can be static and kept on disc.
- Could hold precompiled bytecode for static shaders.

This also includes a new global dependency system.
GLSL shaders can include other sources by using #pragma BLENDER_REQUIRE(...).

This patch already migrated several builtin shaders. Other shaders should be migrated
one at a time, and could be done inside master.

There is a new compile directive `WITH_GPU_SHADER_BUILDER` this is an optional
directive for linting shaders to increase turn around time.

What is remaining:
- pyGPU API {T94975}
- Migration of other shaders. This could be a community effort.

Reviewed By: jbakker

Maniphest Tasks: T94975

Differential Revision: https://developer.blender.org/D13360
---
 source/blender/gpu/intern/gpu_shader_builder.cc | 102 ++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 source/blender/gpu/intern/gpu_shader_builder.cc

(limited to 'source/blender/gpu/intern/gpu_shader_builder.cc')

diff --git a/source/blender/gpu/intern/gpu_shader_builder.cc b/source/blender/gpu/intern/gpu_shader_builder.cc
new file mode 100644
index 00000000000..334bdb2ec58
--- /dev/null
+++ b/source/blender/gpu/intern/gpu_shader_builder.cc
@@ -0,0 +1,102 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2021 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup gpu
+ *
+ * Compile time automation of shader compilation and validation.
+ */
+
+#include <iostream>
+
+#include "GHOST_C-api.h"
+
+#include "GPU_context.h"
+#include "GPU_init_exit.h"
+#include "gpu_shader_create_info_private.hh"
+
+#include "CLG_log.h"
+
+namespace blender::gpu::shader_builder {
+
+class ShaderBuilder {
+ private:
+  GHOST_SystemHandle ghost_system_;
+  GHOST_ContextHandle ghost_context_;
+  GPUContext *gpu_context_ = nullptr;
+
+ public:
+  void init();
+  bool bake_create_infos();
+  void exit();
+};
+
+bool ShaderBuilder::bake_create_infos()
+{
+  return gpu_shader_create_info_compile_all();
+}
+
+void ShaderBuilder::init()
+{
+  CLG_init();
+
+  GHOST_GLSettings glSettings = {0};
+  ghost_system_ = GHOST_CreateSystem();
+  ghost_context_ = GHOST_CreateOpenGLContext(ghost_system_, glSettings);
+  GHOST_ActivateOpenGLContext(ghost_context_);
+
+  gpu_context_ = GPU_context_create(nullptr);
+  GPU_init();
+}
+
+void ShaderBuilder::exit()
+{
+  GPU_backend_exit();
+  GPU_exit();
+
+  GPU_context_discard(gpu_context_);
+
+  GHOST_DisposeOpenGLContext(ghost_system_, ghost_context_);
+  GHOST_DisposeSystem(ghost_system_);
+
+  CLG_exit();
+}
+
+}  // namespace blender::gpu::shader_builder
+
+/** \brief Entry point for the shader_builder. */
+int main(int argc, const char *argv[])
+{
+  if (argc < 2) {
+    printf("Usage: %s <data_file_to>\n", argv[0]);
+    exit(1);
+  }
+
+  int exit_code = 0;
+
+  blender::gpu::shader_builder::ShaderBuilder builder;
+  builder.init();
+  if (!builder.bake_create_infos()) {
+    exit_code = 1;
+  }
+  builder.exit();
+  exit(exit_code);
+
+  return exit_code;
+}
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